Electric pencil sharpener

ABSTRACT

An electric pencil sharpener having a cutter holder rotatably mounted on a casing and rotatably supporting at a desired inclination to the axis thereof a cylindrical cutting member having multiple spiral cutting edges integrally formed theron and facing in the direction of insertion of a pencil to be sharpened. Control means are provided for automatically stopping the sharpener when the operation has been completed and for illuminating a lamp to visually indicate that the pencil has been properly sharpened.

United States Patent 1 1 Nakazaki 1 July 17, 1973 1 ELECTRIC PENCIL SHARPENER 2,979,031 4/1961 Phlibotte 144 287 2,408,767 10 i946 Fl 144 28.5 Inventor: Kenichi Nakazaki, Nagoya,.lapan emmg 73 Ass' e Tok o Sh'bau a El t C Ltd.,

I lgn e i i f g He 0 Prir nary Examiner-Andrew R. .luhasz Assistant Examiner-James F. Coan Flledi p 1971 Attorney-Norman F. Oblon et al. 21 Appl. No.: 181,039

[30] Foreign Application Priority Data [57] ABSTRACT Sept. 16, 1970 Japan 45/80465 Sept. 18, 1970 Japan 45/81240' An electric p l ha p n r h ing a utter holder ro- Sept. 18, 1970 Japan 45/8124] tatably mounted on a as g d ta a ly pp i g at a desired inclination to the axis thereof a cylindrical [52] US. Cl. 144/285, 144/2872 c ing member having multiple spiral cutting edges in- [51] Int. Cl. B43l 23/02 g y formed r n and i g n he ir i n of in- [5 8] Field of Search 144/283, 28.4, 28.5, scrtion f a p i to bc sh rp n Con rol means are 144/285, 28,7, 28,72 provided for automatically stopping the sharpener when the operation has been completed and for illumi- [56] Referen es Cit d nating a lamp to visually indicate that the pencil has UNITED STATES PATENTS been P l sharpened- 3,678,975 7/1972 Imanishi et a1. 144/285 2 Claims, 18 Drawing Figures Patented July 17 1973 5 Sheets-Sheet i INVENTOR KENICHI NAKAZAKI ATTORNEYS Patented July 17, 1973 5 Sheets-Sheet 2 Patented July 17, 1973 5 sheets-sheet 5 FIG.9 v

Patented July 17, 1913 3,746,061

5 Sheets-Sheet 4 Patented July 17, .1973 3,746,061

5 Sheets-Sheet b FIG. 11

ELECTRIC PENCIL SHARPENER BACKGROUND OF THE INVENTION 1. Field of the Invention This invention generally relates to electric pencil sharpeners and more particularly to an improved indicating means for informing the operator of an electric pencil sharpener when the pencil sharpening operation has been completed.

2. Description of the Prior Art Heretofore, in order to apprise the operator of the completion of the pencil sharpening operation, two general types of indicating devices have been employed. These are the signalling type, such as by lamp illumination or sounding a buzzer, as disclosed in U.S. Pat. Nos. 3,486,540 and 3,134,365, both granted to Takeo Hori and the cutter holder-stopping type disclosed in U.S. Pat. No. 2,561,438 granted to Herve R. Duchesneau. In the signalling type, the lamp is illuminated or the buzzer is sounded when the pencil sharpening operation has been completed, while in the cutter holder-stopping type, the cutter holder is automatically stopped through actuation of a control switch by the lead point of the pencil when the pencil sharpening operation has been completed. Thus, in the former, the pencil often is sharpened too deeply because the cutter does not stop, and in the latter, the sharpened pencil is likely to produce hairlike wood chips on the finished surface of the pencil because of the particular direction of the cutting edges, as described hereinbelow.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a new and improved electric pencil sharpener.

It is another object of the present invention to provide a new and improved electric pencil sharpener which will not sharpen the pencil too deeply.

Still another object of the present invention is to provide a new and improved electric pencil sharpener which will not produce hair-like wood chips on the cut surfaces of the sharpened pencil.

A still further object of the present invention is to provide a new and improved electric pencil sharpener in which the cutter automatically stops without producing hair-like wood chips on the cut surface of the sharpened pencil when the pencil sharpeningoperation has been completed.

Yet a further object of the present invention is to provide a new and improved electric pencil sharpener in which an indication lamp is illuminated and the cutter is automatically stopped when the pencil sharpening operation has been completed.

Yet another further object of the present invention is to provide a new and improved electric pencil sharpener which is adjustable to vary the size of the lead point of the pencil.

Briefly, in accordance with the present invention, these and other objects are obtained by providing a casing having an electric motor and a cutter holder rotatably mounted therein. The cutter holder includes a cylindrical cutter rotatably mounted relative thereto and being rotatable around its own axis and about one end of a pencil inserted therein. Multiple spiral cutting edges are integrally formed on the outer surface of the cylindrical cutter extending in the longitudinal direction of the pencil being inserted therein for sharpening and facing in the same direction.

BRIEF DESCRIPTION OF THE DRAWINGS Various other objects, features and attendant advantages of the invention will be more fully appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein like reference numerals designate like or corresponding parts and in which:

FIG. 1 is a plan view of an electric pencil sharpener constructed according to the present invention in which an upper casing is removed;

FIG. 2 is a cross sectional view taken along line 22 of FIG. 1;

FIG. 3 is an exploded view of a cutting means employed in the present invention;

FIG. 4 is a perspective view of a control switch member of the present invention;

FIG. 5 is a diagram of a circuit being utilized to control the pencil sharpening operation of the electric pencil sharpener constructed in accordance with the present invention and shown in cross-section;

FIGS. 6A and 6B are perspective views for illustrating the function of a cutter embodied in the present invention;

FIGS. 7A, 7B and 7C are views when the lead point of the pencil is removed from the cutter of this invention;

FIGS. 8A, 8B and 8C are views when the lead point of the pencil is removed from a well known cutter of the prior art, corresponding to FIGS. 7A, 7B and 7C;

FIG. 9 is a plan view of another embodiment of the present invention;

FIG. 10 is a perspective view of a control switch member of FIG. 9;

FIG. 11 is a diagram of a circuit being utilized to control the pencil sharpening operation of the electric pencil sharpener of FIG. 9;

FIG. 12 is a cross-sectional view of still another embodiment of the present invention; and

FIG. 13 is a perspective view of 'a lead point control means of the embodiment shown in FIG. 12.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings, and more particularly to FIGS. 1 and 2 thereof, an electric pencil sharpener generally designated by the reference numeral 20 includes a lower casing 21 and an upper casing, not shown, which is removably secured thereto. The lower casing 21 houses a sharpener unit 22 having a driving means 23 and a cutting means 24. The driving means 23 are located near a rear wall of the lower casing 21, while the cutting means 24 are positioned adjacent the front wall of the lower casing 21. A U-shaped plate 25 is located between the driving means 23 and the cutting means 24 being secured to the lower casing 21 in order to provide a seal therebetween, and there is a packing 27 between an inner wall of the lower casing 21 and an outer surface of the plate 25. The driving means 23 are provided with an electric motor, such as an induction motor 28, secured to the lower casing 21, and a driving gear 29 is secured to a rotor shaft 30 of the induction motor 28.

As shown in FIG/3, the cutting means 24 features a cutter holder 32 which is rotatably mounted in a hearing member 33 secured to the U-shaped plate 25 by screws, not shown. The cutter holder 32 may preferably be formed of aluminum die-cast material and includes bearing portion 33 at one end and a balance weight portion 34 at the other end, and the bearing portion end 33' is supported in the bearing member 33 having a transmission gear 36 mounted thereon which engages the driving gear 29 of the induction motor 28. Moreover, the cutter holder 32 is provided with an elongate cylindrical cutter 37 which is rotatably mounted in acavity therein on a pin shaft 38 which is in turn suitably secured to the cutter holder 32. The cutter 37 hasa pinion gear 40 at one end thereof which engages an internal gear 41 of the bearing member 33', whereby the cylindrical cutter 37 can rotate about its own axis and also about one end of a pencil 43 which may be inserted in the cutter holder 32,as shown in FIGS. 2 and 3. The cutter holder 32 has an elongate hole 42extending throughthe bearing portion end 33 thereof and a sliding rod 44ismovably inserted therein.

A U-shaped, sliding member "45, is'inserted into the cut- .ter holder32 as shown in FIG. 2 such. that one leg of the sliding member 45;is abutted against'one end of the sliding rod 44 and the, other leg of the sliding member 45 is positioned to be abutted against the lead point of the approac'hingjpencil 43.

As shown in'FlGS. '1 and 2, a'powerswitch'holder 47 is secured to'the bearing member 33 through a switch plate 48and an indication lamp 50 is mounted on the switch plate 48. A shaving box 51 for collecting pencil shavings is removably secured to the lower casing 21 near'the cutter end thereoflj As shown in FIGL'4, a control switch member generally'designa ted by the reference numeral 54 for controlling the pencil sharpening operation is positioned between the cutter holder 32 and the driving means 23 and includes thre'e'leaf contacts 55, 56 and 57 secured in one end of a switch box 58 and being controlled by a movable actuating button 59in the opposite end which may be pushed by an abutment plate 60 by the sliding rod 44,as will be describedlater.

A A controlling circuit is illustrated in FIG. 5, wherein the reference numeral 62 designates a power plug, and

one lead wire 63 thereof is connected to one terminal of the induction motor 28 through normally open contacts 64 of the power switch 47, and'the other lead wire 66 thereof jis-connected to the other terminal of the induction motor 28 through the first and second normally closed leaf contacts 55 and 56 of the control switch 54. The indicating lamp is connected between the lead wire 63 and the thirdleaf contact 57, which'is normally open. vWhenthe pencil sharpening operation has been completed, ethe'sli'ding rod 44' is axially displaced by sliding m'em ber 45 upon contact of the lead point of the pencil43therewith and abutment plate 60 is pivoted thereby to push the button 59. This causes the contacts and 56 of the control switch to be opened, and

face in the same direction as the pencil 43 being inserted into the sharpener. In FIG. 6A, when the cutter 37 rotates about its own axis in a clockwise direction, the edges 65 are also directed in the same direction of the clockwise rotation as well as in the same direction as the pencil being inserted. On the other hand,in FlG. 6B, the edges 65 are generally directed in the counterclockwise direction when the cutter 37 is intended to be rotated about its own axis in the counterclockwise direction.

In operation, when the pencil 43 to be sharpened is inserted into the pencil guiding hole 49 of the power switch holder 47, the normally open contacts 64 of the power switch 47 are automatically closed, so that the induction motor 28 is energized from a voltage supply through the normally closed leaf contacts SS'and 56 of the control switch 54. In this way the pencil sharpening operation is started. At this time, the indicating lamp 50 in the circuit is de-energized by the normally open lead contacts 56 and 57 of the control switch 54. As the sharpening operation goes on until the lead point of the pencil 43 is appropriately sharpened, the sliding rod 44 slides axially by being pushed by the lead point through the sliding member 45, whereby the button59 of the control switch 54 is pushed; by the abutment plate 60.

Therefore, the connection between the second leaf contact 56 and the first leaf contact 55 is opened, and then the connection between the second leafcontact 56 and the third leaf contact 57 is closed, so thatthe induction motor 28 is de-energized and the indicating lamp 50 is subsequently almost immediately illuminated when the pencil sharpening operation has been completed, whereby the'completion of the sharpening operation is indicated by the lamp and the pencil is not out too deeply. In addition, since the spiral cutting edges 65 of the cutter 37fa'cc inthe direction of insertion of the pencil 43, or away from the main body of the pencil, hair-like wood chips 67 are not produced on the cut surface when the pencil 43 is removed from the cutter 37, as shown progressively in FIGS. 7A, 7B and 7C, but instead these chips. are cut away during the withdrawal of the pencil. As compared with the present invention, prior pencil Sharpeners having multiple spiral cutting edges of the cutter directed toward the pencil to be withdrawn, will produce the hair-like wood chips 67 on the cut surface and leave these chips intact thereon, as shown in FIGS. 8A, 8B and 8C.

in FIGS. 9 through 11, another embodiment of the present invention is illustrated. The reference numeral 68 designates a hook lever rotatably pivoted on the plate 25, being urged in a counterclockwise direction, as viewed in FIG. 10, by a first spring 69 secured to one end to the plate 25. An operating member 70 has three nails surrounding the pencil being inserted into the sharpener and one of the nails is employed to control the normally open contacts 64 of the power switch 47 to close and open the same-.The second nail of the op erating member 70 is urged in the direction of the cutter holder axis center by a second spring 71, the force of which is stronger than that of the first spring 69. The other end of the lever 68 and the second nail of the operating member 70 are connected to each other through a flexible wire 72, so that the lever 68 is normally urged in clockwise direction, while the operating member 70 is normally urged in the direction of the cutter holder axis.

In accordance with this embodiment, when the sharpening operation of the pencil has been completed, the induction motor 28 is stopped and the indicating lamp 50 is illuminated, and the induction motor 28 cannot be restarted until the sharpened pencil is completely withdrawn from the socket 49. Namely, the hook lever 68 engages the abutment plate 60 when the plate cams itself over the hook end during actuation by sliding pin 44, contacts 55 and 56 of the control switch are maintained in an open position, and the contacts 56 and 57 of the control switch 54 are maintained in a closed position.

In a further embodiment of the present invention shown in FIGS. 12 and 13, the reference numeral 74 designates a control means having a cam plate 75 secured to the plate 25, a cam shaft 76 rotatably mounted in the plate 75 and a switch lever 79 rotatably mounted on the cam plate 75. The cam shaft 76 is provided with a cam 77 on one end thereof and a dial 78 on the other end thereof. The switch lever 79 is urged in a counterclockwise direction, as viewed in FIG. 13, by a spring 82. A pin 83, such as an adjustable screw, is mounted on the switch lever 79 to abut against an annular surface of the cam 77. The switch lever 79 also includes a control switch 54 and an abutment plate 60.

In accordance with the above embodiment, the size of the lead point of the pencil being sharpened may be changed as follows. When the dial 78 of the control means 74 is rotated, the abutment position of the pin 83 of the switch lever 79 to the annular surface of the cam 77 is altered, whereby the switch lever 79 rotates on the cam plate 75 and takes a suitable new position, such that the gap between the sliding rod 44 and the control switch 54 is suitably adjusted. in this way, the size of the lead point of the pencil 43 can be easily changed.

Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.

What is claimed as new and desired to be secured by Letters Patent of The United States is:

1. An electric pencil sharpener comprising:

a casing;

an electric motor mounted in said casing;

a cutter holder rotatably mounted in said casing;

means connecting said electric motor and said cutter holder for rotating said cutter holder;

a cylindrical cutter rotatably mounted in said cutter holder;

multiple spiral edges integrally formed on said cutter surface and facing in the same direction as a pencil being inserted into said cutter holder;

means for rotating said cutter about its axis while said cutter holder rotatably supporting the same is being rotated by said electric motor, whereby said cutter is also rotated about one end of said pencil inserted in said cutter holder;

control means having a cam plate mounted on said casing;

a cam shaft rotatably mounted on said cam plate;

a dial mounted on one end of said cam shaft;

a cam mounted on the other end of said cam shaft;

a switch lever rotatably mounted on said cam plate;

a control switch mounted on said switch lever;

mean for adjusting the position of said control switch relative to said cam shaft; and,

means disposed between said cutter and said switch lever and engageable by said pencil being sharpened for actuating said control switch for stopping the rotation of said cutter holder when the pencil sharpening operation has been completed.

2. An electric pencil sharpener comprising:

a casing;

an electric motor mounted in said casing;

a cutter holder rotatably mounted in said casing;

means connecting said electric motor and said cutter holder for rotating said cutter holder;

a cylindrical cutter rotatably mounted in said cutter holder;

multiple spiral edges integrally formed on said cutter surface and facing in the same direction as a pencil being inserted into said cutter holder;

means for rotating said cutter about its axis while said cutter holder rotatably supporting the same is being rotated by said electric motor, whereby said cutter is also rotated about one end of said pencil inserted in said cutter holder;

indicating means mounted in said casing for stopping the rotation of said cutter holder when the pencil sharpening operation has been completed;

detecting means for detecting the presence of the lead point of said pencil being sharpened at a predetermined position in said cutter holder;

means responsive to said detecting means for actuating said indicating means when said pencil lead point is at said predetermined position to stop said sharpening operation; and

means for preventing de-actuation of said indicating means until said pencil is completely withdrawn from said cutter holder. 

1. An electric pencil sharpener comprising: a casing; an electric motor mounted in said casing; a cutter holder rotatably mounted in said casing; means connecting said electric motor and said cutter holder for rotating said cutter holder; a cylindrical cutter rotatably mounted in said cutter holder; multiple spiral edges integrally formed on said cutter surface and facing in the same direction as a pencil being inserted into said cutter holder; means for rotating said cutter about its axis while said cutter holder rotatably supporting the same is being rotated by said electric motor, whereby said cutter is also rotated about one end of said pencil inserted in said cutter holder; control means having a cam plate mounted on said casing; a cam shaft rotatably mounted on said cam plate; a dial mounted on one end of said cam shaft; a cam mounted on the other end of said cam shaft; a switch lever rotatably mounted on said cam plate; a control switch mounted on said switch lever; mean for adjusting the position of said control switch relative to said cam shaft; and, means disposed between said cutter and said switch lever and engageable by said pencil being sharpened for actuating said control switch for stopping the rotation of said cutter holder when the pencil sharpening operation has been completed.
 2. An electric pencil sharpener comprising: a casing; an electric motor mounted in said casing; a cutter holder rotatably mounted in said casing; means connecting said electric motor and said cutter holder for rotating said cutter holder; a cylindrical cutter rotatably mounted in said cutter holder; multiple spiral edges integrally formed on said cutter surface and facing in the same direction as a pencil being inserted into said cutter holder; means for rotating said cutter about its axis while said cutter holder rotatably supporting the same is being rotated by said electric motor, whereby said cutter is also rotated about one end of said pencil inserted in said cutter holder; indicating means mounted in said casing for stopping the rotation of said cutter holder when the pencil sharpening operation has been completed; detecting means for detecting the presence of the lead point of said pencil being sharpened at a predetermined position in said cutter holder; means responsive to said detecting means for actuating said indicating means when said pencil lead point is at said predetermined position to stop said sharpening operation; and means for preventing de-actuation of said indicating means until said pencil is completely withdrawn from said cutter holder. 